Submarie wellhead apparatus



July 20, 1965 R. K. LE RouAx 3,195,638

SUBMARINE WELLHEAD APPARATUS ATTOH/VEKJ July 20, 1965 R. K. LE RouAx SUBMARINE WELLHEAD AP?ARATUS 2 Sheets-Sheet 2 Filed Aug. 3, 1959 IN V EN TOR.

/EUTUR/VE 5 United States Patent C) l UEP/iifailii. WEL-EEAD APPARATUS Robert K, Le Ronan, Houston, Tex., assigner to Cameron iron Works, Inc., Houston, Terr., a corporation oi Terras Filed Ang. 3, i959, Ser. No. 831,385 9 Claims. (Ci. 16o-56.5)

This invention relates generally to well apparatus; and, more particularly, to improvements in wellhead equipment for use on wells at offshore locations.

It has been the practice heretofore to drill and complete offshore wells from large platforms which are eX- pensive and present navigation hazards. This is particularly true when the iioor of the body of water is at a great depth below the water level.

These di'lliculties could be eliminated if the wells were completed at the door. However, with the wellhead equipment presently availabl subsequent repairs or adjustments to the Christmas tree would require either that the well be killed prior to raising the tree or that divers be sent down to the tree. This latter procedure would limit the well locations to depths of approximately one hundred feet beneath the surface of the water.

An object of this invention is to provide equipment for completing an offshore well at the iloor of the body of water which enables the Christmas tree to be repaired or adjusted without either a rig for ltilling the well or the use of divers.

Another object is to provide such equipment which is operable to raise and lower the Christmas tree to and from the surface of the water without interrupting well ow.

Still another object is to provide such equipment which has minimum power requirements and which is simplilied and inexpensive to construct.

These and other objects are accomplished, in accordance with the present invention, by means of apparatus in which the Christmas tree is supported above the tubing head of the wellhead by an expansion joint. This joint iluidly connects the flow path through the tree with the well tubing, and means are provided for expanding and retracting the joint to raise and lower the tree with respect to the head. More particularly, the upward thrust on the joint is at least substantially balanced so that the tree may be raised and lowered with a minimum of eX- penditure of power.

In the drawings, wherein like reference characters are used throughout to designate like parts:

FIG. l is a diagrammatic view of welihead equipment having the Christmas tree thereof supported by an eX- pansion joint constructed in accordance with the present invention and in its lower position;

FIG. 2 is a view of the wellhead equipment of FIG. l on an enlarged scale and partly in section;

FG. 3 is a diagrammatic view similar to FlG. l; but in which the expansion joint has been extended to raise the Christmas tree to a position above the water level tor repair or adjustment, and

FIG. 4 is a view similar to FlG. 2, but showing the equipment thereof in the raised position of FIG. 3.

Turning now to a detailed description of the drawings, the Christmas tree shown diagrammatically in FlGS. l an 2 includes a master valve it?, a T ll connected above the master valve, and a lift ring llo connected above the T. A wing valve 12 is connected to the side outlet o the T, and a choke 13 is connected to the opposite end of the wing valve. A flow line 3.4 connects to the choke for conducting the well iiuid from the Christmas tree to a suitable storage point.

These elements are basic to a conventional Christmas Patented July 2G, i965 ice tree, and such term, when used in the specification and claims, is to be so construed. 0f, course, the tree may .include additional elements or modiiications to the elements shown and described. In any case, however, the function of the tree is to conduct well duid from within the well and through the welihead to the ow line. For this purpose, the various elements described provide a ilow path for well iluid from the inlet to the master valve to the outlet from the choke.

The tree is supported above the tubing head l5 of the wellhead 3 6 by means of an inner tubing i7 forming part of the expansion joint to be described. As shown in 3, the casing head iS of the wellhead is securely mounted on the door i9 of the body of water at a substantial depth beneath the water level 29, and the tubing head l5 is connected above the casing head by ilanged connections, in a manner well known in the art and best shown in FIG. 4. More particularly, the tubing head is connected above the casing head by means of bolts 2l with the bore 2.?. therethrough aligned with the bore 23 through the casing head.

A string of casing 24 is threadedly connected to the lower end oi the bore 23 of the casing head for suspension therefrom, and an inner string of casing 25, known as the oil string, is suspended within the casing head in spaced Arelation to the outer casing 2d by means of a conventional type of casing hanger 26 seatable within a tapered bowl 27 in the bore of the head. The annulus between the inner and outer casings is isolated by means of a seal ring 23 on the casing hanger.

An outer tubing 29 of the expansion joint is suspended from the tubing head l5 by means of a tubing hanger 36 at its upper end which seats within the tapered bowl 3l in the bore of the tubing head. This outer tubing 29 eX tends downwardly through the bore 22 of the tubing head and the inner casing .25 in spaced relation thereto to deiine an annulus 32 therebetween. lt also surrounds the inner tubing i7 in spaced relation thereto for a purpose to be described below.

A tubin r string 33 is threadedly connected to the lower end of the outer tubing 29 for extension downwardly within the well to a level for conducting the well fluid to the wellhead. More particularly, the lower end of the outer string 29 carries seal means 34 which sealably engage the inner tubing 17 during reciprocation therebetween so as to confine the ilow of well uid upwardly through the tubing string 33 into the inner tubing 17 and thus into the Christmas tree.

Another seal means 3S is carried by the tubing hanger 3l? on the upper end of the outer tubing Z@ for sealably engaging the inner tubing i7 above the seal means 34 during the reciprocation of the inner tubing. Thus, these two seal means deiine an annular chamber 36 between the inner and outer tubings. A piston 37 carried by the inner tubing l sealaoly engages the outer tubing 29 during reciproca-tion of the inner tubing to divide the chamber 36 linto upper portion 33 and lower portion 33a.

A port 39 in the inner tubing 17 connects the interior thereof with the upper chamber portion 3S above piston 37 to 4admit well uid thereto. More particularly, the cross-sectional area 4of the piston 37 within chamber portion 3S is at least as great as that of the portion of the inner tubing 17 which is slidable through the lower seal means 3d. In this manner, the upward thrust on the inner tubing due to well pressure therebelow is offest by the downward force resulting from the iniluence of well iluid on the top of the piston 37. Thus the inner tubing l? is substantially pressure balanced so that there is a minimum ci power required for either raising or lowering the Christmas tree supported above it.

The tubing hanger 39 is 'held down in seated position by extendable and retractable locking screws 40 on the head 15, and sealing members 41 about thehanger sealingly engaging the bore of the tubing head when the hanger is in seated position to close off the upper end of annulus 32. Also, sealing rings 42 are received in counterbored portions on the lower end of the bore of the tubing head to seal between the tubing head and the upper end of the oil string 25.

It may be found that the tree can be lifted merely by attaching a hoisting line 43 (see FIG. 3) to the lift ring 11a of the Christmas tree. Obviously, slacking olf on the line would permit the tree to be lowered by its own weight. However, it is preferred that the tree be raised and lowered by means of fluid pressure admitted through a port 44 in the -outer tubing 29 connecting the exterior thereof with the portion 38a of the chamber 36 beneath piston 37. That is, the force due to upon the lower side of piston 37 Vis effective to urge the inner tubing upwardly. Obviously, when the pressure of such fluid is suciently high to provide a force greater than the weight of the tree and inner tubing, the tree will be raised. Then, upon controlled reduction of the pressure of such fluid, the tree may be lowered.

Preferably, pressure uid for this purpose is conducted into the annular space 32 from above the water level and is confined within such space for passage through the port 44 by means of a seal ring 45 about the outer tubing and sealingly engageable with the interior of the oil string 25 beneath the port 44. More particularly, there is a side opening 46 in the tubing head connecting with the space 32 beneath the seal means 41 on the tubing hanger and above the sealing member 45, and a conduit 47 connects with the outer end of the opening 46 for extension upwardly to the water level, as shown in FIGS 1 and 3.

When lthe'tree is lowered, as shown in FIG. 1, the upper end of this conduit is carried by a float marker 48. When, however, the tree has been raised, as shown in FIG. 3, the upper end of the conduit 47 is connected to a 'suitable source 49 of pressure duid carried by a barge t) or other sea-going craft. As can be seen from FG. 3, this barge is located adjacent the Christmas tree so that an operator may adjust or repair the Christmas tree from it.

Obviously, when itis desired to raise the tree from the position of FIGS. l and 2 to rthe position of FIGS. 3 and 4, the conduit 47 is connected to the source 49 and pressure fluid is admitted to the lower chamber portion 38a through the port 44 for moving the piston 37 upwardly and thus raising the tree above the water level. The upper limit of movement of the tree is determi-ned by stop parts 51 on the interior of the outer tubing for engagement with the upper end or piston 37, as shown in FIG. 4. Upon lowering of the tree, the inner tubing 17 is movable downwardly to a position limited by the engagement of piston 37 thereon with the upper end of lower seal means 34 carried by the outer tubing. Obviously the length of the inner tubing 1'7 will be dependent upon the depth of the water at the offshore location and,

for this reason, such tubing as well as the conduit 47 have been shown broken in the drawings. p

A coverl in the form of a flange 52 is connected over the upper end of the tubing head by means of bolts 53 and ,rovided with an -opening 54 carrying seal ring 55 for slidably engaging the inner tubing above upper seal means 3.5. A recess on the lower end of the opening 54 surrounds seal rings 56 on an upwardly extending neck of the hanger 30.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set for-th, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcom-binations are of utility and may be employed wit-hout pressure fluid actingy eference to other :features and subcornbinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood -that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

ll. Well apparatus, comprising a wellhead having a bore therethrough, a iirst hanger within the wellhead for suspending a casing therefrom, a second hanger within the wellhead for suspend-ing a tubing concentrically within the casing, through for connecting with :a ow line, an expansion joint including a tubular member passing through the tubing hanger to support the tree above the wellhead and fluidly connect the flow path of the tree wi-th the tubing, means yfor extending and retracting the tubular member to raise and lower the tree with respect to the wellhead, and pressure responsive means on the tubular member beneath the upper end of the wellhead for balancing the upward force on the tubular member due to the well pressure on the lower end of the tubular member in all.

positions of said tubular member.

2. Wellhead equipment, comprising a wellhead having a bore therethrough, ,a casing hanger seatable in the bore to suspend a casing therefr m, tubingl means including an outer tubing and a tubing hanger on the upper end of the outer tubing lseatable in t-he bore of the wellhead to suspend the outer tubing from the tubing head and means on the lower end of the outer tubing to suspend a tubing string within the casing, said outer tubing spaced from the bore of the wellhead to provide an annulus between the outer tubing and said bore and the casing, an inner tubing within the outer tubing in spaced relation thereto and extending through the upper end ofthe tubing hanger and adapted to support 1a Christmas tree above the wellhead, spaced apart 4seal means on the tubing means and sealably and slidably surrounding the inner tubing to define an annular chamber between the inner tubing and tubing means, a piston on the inner tubing sealably slidable over the outer tubing within thev chamber, a port in the inner tubing connecting with the chamber above the piston for admitting well duid thereto, and an opening in the tubing means connecting with the chamber below the piston for admitting fluid thereto, the annular pressure responsive area of said piston within the portion of the chamber above said piston being at least as large as the cross sectional area of the portion of the inner tubing slidable within the lower seal means on the outer tubing.

3.V Wellhead equipment of the character defined in claim 2, including means for sealing a portion of the annulus between the outer tubing and the bore and casing beneath wellhead connecting with Y the annulus, and a conduit connected with the port in the wellhead and extending upwardly therefrom for supplying pressure uid from surface level to the annulus and lower portion of the chamber.

4. Wellhead equipment, comprising a wellhead having a bore therethrough, tubing and a tubing hanger on the upper end of the outer tubing seatable in the bore of the wellhead to suspend the outer tubing from lthe wellhead in spaced relation to the bore therethrough to provide an annulus ltherebetween, means on the outer tubing for suspending a tubing string from its lower end, an inner tubing within the outer tubing in spaced relation thereto and extending through the upper to support a Christmas tree above the wellhead, a pistonl on the inner tubing sealably slidable within the tubing means, seal means on the tubing means and sealably and slidably surrounding the inner tubing on opposite sides of thepiston to define annular chamber portions, a port a Christmas tree having a flow path therethe opening in the tubing means, a port in theltubing means including an, outer end of the tubing hanger and adapted' in the inner tubing connecting with the upper chamber portion for admitting well fluid thereto, and a port in the tubing means connecting with the lower chamber portion for admitting uid thereto, the annular pressure responsive area of the piston within the upper chamber portion being at least as large as the cross-sectional area of Ithe portion of the inner tubing slidable within the lower seal means on the tubing means.

5. Weilhead equipment of the character defined in claim 4, wherein the wellnead has an opening therein connecting its bore with the exterior thereof, and including a conduit connecting with the outer end of the opening for extension upwardly therefrom.

6. Wellhead equipment, comprising tubing means including an outer tubing and a tubing hanger on t'ne upper end of the outer tubing means on the outer tubing for suspending a tubing string from its lower end, an inner tubing within the tubing means in spaced relation thereto and extending through the upper end of the tubing hanger, means on the inner tubing for supporting a Christmas tree from its upper end, spaced apart seal means on the tubing means and sealably and slida'oly surrounding the inner tubing to deine an annular chamber between the tubings, piston on the inner tubing sealably slidable over the outer tubing within .the chamber to deine upper and lower chamber portions, a port in the inner tubing connecting with the upper chamber portion for admitting well fluid thereto, and a port in the tubing means connecting with the lower chamber portion for admitting fluid thereto, the annular pressure responsive area of said piston within the upper chamber portion being at least as large as the cross-sectional area of the portion of the inner tubing slidable within the lower seal means on the tubing means.

'7. Wellhead equipment of the character dened in claim 6, including seal means about the tubing means beneath the port therein.

S. Well apparatus, comprising a wellhead having a bore therethrough, a first hanger within the wellhead for suspending a casing therefrom, a second hanger within the wellhead for suspending a tubing within the casing, a Christmas tree having a ow path therethrough for connecting with a owline, an inner tubing supporting the tree above the tubing head and passing through the second hanger for liuidly connecting the ow path of the tree with the tubing suspended from the second hanger, means for extending and retracting the inner tubing to raise and lower the tree with respect to the wellhead, means sealing between the second hanger and inner tubing during extension and retraction of the inner tubing, and pressure responsive means on the inner tubing beneath the upper end of the wellhead for balancing the upward force on the inner tubing due to the Well pressure on the lower end of the inner tubing in all positions of the inner tubing.

9. Well apparatus of the character defined in claim 8 wherein said last-mentioned means includes a piston carried by the inner tubing for sealably sliding within the tubing suspended from the second hanger, and a port connecting the interior of the inner tubing with the eX- terior thereof above said piston, the pressure responsive area on the upper end of said piston being at least substantially equal to the pressure responsive area on the lower end of said inner tubing.

References Cited by the Examiner UNITED STATES PATENTS BENJAMN HERSCH, Primary Examiner. BENJAMN BENDETT, CHARLES E. QCONNELL,

Examiners. 

1. WELL APPARATUS, COMPRISING A WELLHEAD HAVING A BORE THERETHROUGH, A FIRST HANGER WITHIN THE WELLHEAD FOR SUSPENDING A CASING THEREFROM, A SECOND HANGER WITHIN THE WELLHEAD FOR SUSPENDING A TUBING CONCENTRICALLY WITHIN THE CASING, A CHRISTMAS TREE HAVING A FLOW PATH THERETHROUGH FOR CONNECTING WITH A FLOW LINE, AN EXPANSION JOINT INCLUDING A TUBULAR MEMBER PASSING THROUGH THE TUBING HANGER TO SUPPORT THE TREE ABOVE THE WELLHEAD AND FLUIDLY CONNECT THE FLOW PATH OF THE TREE WITH THE TUBING, MEANS FOR EXTENDING AND RETRACTING THE TUBULAR MEMBER TO RAISE AND LOWER THE TREE WITH RESPECT TO THE WELLHEAD, 